Carburetor



Fb. 23, 1932. E. T. BUSH ET AL 1,846,789

CARBURETOR Filed May 2, 1930 2 Sheets-Sheet 1 ATTORNEYS.

Feb. 23, 1932. E. T. BUSH ET AL CARBURETOR Filed May 2, 19:50 2 Sheets-Sheet 2 ATTORNEYS.

Patented Feb. 23, 19.32

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Mai-9 ASSIGNOIBS oromrnmnro-nomm Q..ETGES,.OFLOS-ANGMICALIFOBNIA M o u'r inventionfrelates to carbureters and particularly to that type of-carbureter having .a Venturi tu'bewhieh is adjustable or variabl as to size for the purpose of conof thefuel mixture delivered tothe engine. The adjustable Venturi tube" is operable"by the en 'ine 'with whichit.is'fassoeiated and throng 1 'tlie medium ofa centrifuge so asto befvarieble in size *in accordaneewith the arbureters of this type, 'although providing many advantages over the fixed or nonvariable Venturi tube, are nOt-wh'oll "efli cient for-the reason that the Venturrtube heing' yerieble insize in'direet accordance with the variationin engine speed, causes the carbureter to emit therichest mixture "of which it is eaiiable when the-engine isoperating-at a low-speed. "It is appreciated that such a' mode of operation is 'ofvalue when startinga cold motor, as well as when the engine is epe 'atingeta relatively low speed and-H nder heavy load, but when the engine is "ao'p'erating at its proper temperature and; at 811 idling- 0rlow speed, an extremely 'fr oh -mix-ti1r is-delivered to the engine which results-infui-idileheating of the engine, unnecessary ebnsnm'ptionof fuel',and the emiss on of unbur nt gases rich in carbon monoxide and hence highliy- 'injnrioilsto human life. Further, by" e'mp dying a. driving 'conneetion t6-0perate the Ventnri tnbe in accordance with the engineyspeed, mechanical and lubri'cating difiieulties are presented, aside from the expense of manufacture and installation.;'

- It is a purpose-of our invention to provide in a eerbureterhaving avariable Ve n turi tube, a mechanism for automatically ad-v justing the Vent-uriftube byand'in accordance withthes'uotionproduoed in the intake manifold of the engine and whereby,-- the functional and structural disadvantages atp tendant a mechanism operating the *V enturi tube in accordance with engine speed a're eliminated while the advantages thereof are A retained and augmented by} a difierent mode of operation.

- claims. 1 trolling the air flow through the carbureting chamber, and hence, thedegree-of richness Y embodying our, invention;

-end elevation and partly in sctibiii i fWe will dese1fihe only' In orm mgrbureto'r embodying our invention; andwill then point out the novel features f in Fig. 2 is a viewshowin the caibuteterin Fig. 3'is a view showingtheiearhuret' side-elevation:

' f Fi :4 is a, vetti'cmlsectidiiel view'tnkenen "the llne fand coking in the direction "of the arrows.- 7 I '*f*"";

*Figgfi a horizontal sectional-view taken "on the line 5+5 of'Fig. 2 and oo'king i direction-ofthe arrows. 1 q 1 In oarrying'eut our invention, we liioviile a carbureter; which includes an L-sheped pipe a the horizontal p rtibn 15-"0f-wh1eh,

' constitutes an air inlet "and' c'ontain'sf a' cert ventionaliforin of choke val-tie 1L6; 4 Thefven tical portion 17 of the 'pipe' i ed'apted"or connection" at'its 'upper end-" td" the -intake manifold of an internal "comhnsti'on engine (not shown), and this=portioii of thipifie containse conventional throttle valve; 18 for controlling the discharge of the gase'oius mixture -=froin "the carbureter and int 'the'manL' fold. Below the throttle val "the,15i1ie1 is formed, with" lateralenlargements- 1 93111 whieh anadjustable Venturitnhei's'rnoiinted.

- This tube consists, i n the pisentinstinee, of

two cylindric l parts 20 having stuh shafts at -thei r' :ends journaled in -.ipl9.tes' secured P by means of serews 23t0' opiio'sit'e sides oftlie are 'recessedat two point'sgindic'eted' 13 20 -and Q0", tov provide a'throat 20 between the art'sfwhich in reality 'eonstitiites the eiitnritnbe." The diameter of -=tl1'is'=throat"2( is'variableby'rotation of the rte 2Q, in consequence,- such adjnstment is ope hie to vary'the fi'moun't'of sir-flowing hr gh the ipe;

The receding description of the Venturi 7 tube is elieved tosuflice for the purpose, as

[its specific construction forms no part of our invention other-than it should be adj ustable to vary the air flow through the carburetor.

The two parts are a apted to be rotated simultaneously and in opposite directions by means of gears 24 forme on one end of the parts as best illustrated in Fig. 5. One stub axle 21 has secured thereto an arm 25, and through the medium of a connecting rod 26 this arm is operatlvely connected to a piston 1 T of what ma be termed a vacuum pump.

As shown in Figs. 1 and 2, the rod '26 extends into the bifurcated end of the piston T where it is secured by means of a transverse pin 27. The piston T operates in acylinder C which is preferably cast integral with the adjacent plate 22, and by reference to Fig. 2 it will be i having on its inner end a flat head 34 cn-.

gaging the s ring and on its outer end a knurled han le 35 by which the screw can be rotated in one direction or the other to advance or retract the head 34 to increase or decrease tension of the spring 30. A lock nut 36 maintains any adjustment of the screw 32, and it will be noted that the head 33 is threaded in the end of the cylinder to permit assembling and disassembling of the parts received b the cylinder.

Under t e action of the spring 30, the piston T is yieldably urged to the right as when viewedin Fig. 1 in order to yieldin ly maintain' the Venturi tube in its smallest osition of adjustment in which the throat as of the smallest diameter. To move the tube to larger positions of adjustment in order to increase the diameter of the throat, we utilize the suction produced in the pipe P as a result of the air drawn therethrough when the carburetor is associated with the intake 7 manifold of an engine. For this purpose we provide a pipe 37 connected at one end to a passage 38 formed in'the cylinder C and communicating with the interior'thereof at the I spring side of the piston T. Theopposite end of the ipe 37 extends into the pipe P at a point a (we theVenturi tube and referabl although notnecessarily, above t e thrott e valve 18. Thus,.the air drawn through the low, it will operate to pipe P produces a negative air pressure in the cy in der C at the spring side of the piston T, and when this negative pressure is sufliciently move the pistonto the of the left and against the tension-of thespring i 30. I The intensity of the negative pressure or suction induced in the c linder C may be regnlated by means of a va ve 39 threaded' t e c linder and controlling the passage of air through the assage 38. This valve may be nut 40.

I Formed integral with or secured to one of the plates 22 is a float chamber 41 from which extends a fuel nozzle 42 so that the outlet end thereof is disposed within a carbureting chamber 43 provided in the vertical ortion ipe P below the parts ofthe enturi tube. The nozzle 42 is positioned directly below the throat ofthe Venturi tube,

so that secured in a justed position by means of a air drawn upwardly throu h thepi e P will cause fuel to be discharged or intermixing with the air to combustible mixture.

- The operation of the carburetor is as follows With the carburetor associated with the intake manifold of an engine, and the throttle a-Ive 18 closed so that the engine is operatingat an idling s eed, the suction produced in the ipe 37 is at a maximum. In consequence, t e negative pressure produced produce the y in the cylinder C is at a maximum and therefore the 1piston T is pulled to its extreme osition at t 1e left and against the tension 0 the spring 30 to open the Venturi tube to its largest position of ad'ustment, that is, a position in which the diameter of the throat 20 is the largest. As a result of this opening of the Venturi tube, a relativelylean mixture is supplied to the engine, but one suf ficient to maintain the engine operatin at an idling speed. With opening of the t rottle valve 18 to accelerate the speed of the engine, the suction produced in the pipe 37 naturally decreases so that under the action of the spring 30 the piston T begins to move to the right, as when viewed in Fig. 1, thereby op erating theparts of the Venturi tube to re- .duce the diameter of the throat 20. Thus,

the volume of air flow through the carbureting chamber decreases with opening of the throttle valve and, as a consequence, the fuel mixture increases in richness. However, this condition does not exist throughout the entire speed range of the engine for it will be understood that as the speed of the en ine ini creases through opening of the thrott e valve,

fromt e nozzle the suction produced in the intake manifold Q likewise increases. This increase in suction acts through the pipe 37 to move the piston T again to the left, and as a consequence, the

Venturi tube now begins to open so that with V the engine operating at a relatively. high speed ;a relatively lean mixture is supplied to the engine.

From the receding operation it should be manifestt at adjustment of the Venturi tube is effected and controlled by the intensity of the suction produced in the pipe 37 and not by the speed of the engine, for it will produce a suction in the cylinder for moving be understood that when the engine is opthe piston against the action of said urging crating under a heavy load and the throttle means to'open the tube. wide open, the speed of the engine may be EARL T. BUSH. 5 relatively'low and yet the efiective suction ALBERT J. SOWER.

in respect-t0 the pump is sufiicient to produce a minimum adjustment of the Venturi tube to allow a maximum supply of fuel to the engine and thus insure the operation of the engine under a heavy load. 75

Although we have herein shown and described only one form of carbureter embodying our invention, it is to be understood that various changes and modifications may be made therein without departing from the r 8a spirit of the invention and the spirit and sco e of the appended claims. 7

e claim as our invention: L In a carbureter, a carburetin chamber through which air is adapted to ow in response to suction produced in the intake manifold, a Venturi tube having two parts relatively rotatable to occupy one extreme position in which the effective cross sectional area 25 of the tube is reduced and another extreme position in which said area is enlarged, means tending to rotate said parts to the first extreme position, and means responsive to suetion produced in the intake manifold for to j 0 tating said parts to the other extreme posiv tion and to intermediate ositions..

2. In a carbureter, a carbureting chamber, a Venturi tube adjustable to vary the amount of air flowing through the carbureting cham- J 35 ber, urging means tending to close the tube,

a pump for opening the tube, a throttle valve in the carbureting chamber, and a connection between the pump and the carbureting' chamber beyond the throttle valve by which 40 a suction can be produced in the cylinder of j the pump in consequence of air flowing through the chamber to actuate the pump.

3. In a carbureter as embodied in claim 2' wherein the urging means comprises a spring engaging the piston, and a member adjustno able in the cylinder to vary the efiective tension of the spring in respect to the piston.

4. In a carburetor, a carbureting chamber, 50 a Venturi tube adjustable to vary the amount 5 of air flowing through the carbureting chamher, a pump including a cylinder and a piston movable in the cylinder and operatively connected to said tube so as to effect adjustment of the latter to open or close the tube accordmg as the piston is moved in one direction or the other, yieldable and adjustable means for urging the piston in one direction to close said tube, comprising a spring engaging and l 60 having a part extending into the piston, and i a screw threaded in the cylinder and (211- I gagmg the spring for varying the tensionof the spring, and a connection between the cyllnder and the carbureting chamber for per- 66 mltting the air flow through the chamber to 330 

